I work in a scientific institution and one of the tasks I'm currently working on involves running simulations and outputting the data it produces on-the-fly to hard disk. When I say 'on-the-fly', I mean that the program itself spits out data to disk every second or so. These simulations are written purely in single thread C++ and are run on a Mac Pro. The relevant specifications of this Mac are as below:
OSX Version: 10.6.8 Model Name: Mac Pro Model Identifier: MacPro4,1 Processor Name: Quad-Core Intel Xeon Processor Speed: 2.66 GHz Number Of Processors: 2 Total Number Of Cores: 8
The Intel Xeon's are hyperthreaded for up to 8 virtual cores
I execute my simulations in a simple .sh file, using the following syntax:
nohup simulation1.o configfile 2> /dev/null > /dev/null & nohup simulation2.o configfile 2> /dev/null > /dev/null &
and so on...
Using nohup means that I don't need to worry about random disconnects when I work remotely.
When I look at
ps after running, say 10, simulations using my bash file, I find that in the STATE column, the processes switch regularly from 'running' to 'stuck'. Furthermore, I would expect the CPU usage to be 100% for each process, but each process averages about 28% each instead. (My expectation that the CPU usage be 100% for each process is that when I run just one of these simulations, the CPU column is maxed at about 100%, added to the fact that the cores have hyperthreading. These are very CPU heavy simulations.)
Does anyone know what's going on? Specifically:
- What does 'stuck' mean, in relation to
- Why is the CPU not maxed out for each process?
I'd appreciate some help greatly.